1. If 200 volts are put across a 300-loop transformer's primary coil:
   1. What will be the voltage output if the secondary coil had 750 loops?
   2. What is the power in the secondary coil if the resistance in this coil is 50 ohms?
   3. What is the current drawn in the primary coil?
   4. What is the power in the primary coil?
2. A model electric train requires 6 volts to operate. If the primary coil of its transformer has 240 windings, how many windings should the secondary have if the primary is connected to a 120-volt household circuit?
3. How does the current in the secondary of a transformer compare to the current in the primary if the voltage in the secondary is three times the voltage in the primary?
4. Define the following terms:
   1. Critical angle
   2. Total internal reflection
   3. Penumbra
   4. Umbra
5. Distinguish between reflection and refraction.
6. Distinguish between a converging lens and a diverging lens.
7. When a fish looks up at an angle of 45 degrees with the horizon, does it see the sky or the reflection of the bottom beneath? Explain why.
8. Compare the characteristics and functions of the rods and the cones of the eye.
9. Distinguish between a virtual image and a real image.
10. What kind of lens can produce a real image? A virtual image?